Gnu.Getopt.Getopt.exchange C# (CSharp) Method

        private void exchange(string[] argv)
        {
            int bottom = this.firstNonopt;
            int middle = this.lastNonopt;
            int top = this.optind;
            string tem;

            while (top > middle && middle > bottom)
            {
                if (top - middle > middle - bottom)
                {
                    // Bottom segment is the short one.
                    int len = middle - bottom;
                    int i;

                    // Swap it with the top part of the top segment.
                    for (i = 0; i < len; i++)
                    {
                        tem = argv[bottom + i];
                        argv[bottom + i] = argv[top - (middle - bottom) + i];
                        argv[top - (middle - bottom) + i] = tem;
                    }
                    // Exclude the moved bottom segment from further swapping.
                    top -= len;
                }
                else
                {
                    // Top segment is the short one.
                    int len = top - middle;
                    int i;

                    // Swap it with the bottom part of the bottom segment.
                    for (i = 0; i < len; i++)
                    {
                        tem = argv[bottom + i];
                        argv[bottom + i] = argv[middle + i];
                        argv[middle + i] = tem;
                    }
                    // Exclude the moved top segment from further swapping.
                    bottom += len;
                }
            }

            // Update records for the slots the non-options now occupy.

            this.firstNonopt += (this.optind - this.lastNonopt);
            this.lastNonopt = this.optind;
        }